Aktivhaus B10 networks the electric vehicles and the building in an overarching, integral system. This system is controlled using an app developed especially for the project. Particular attention was paid to the design of the user interface as it is where all interactions between the user and the system take place. As a consequence, the user interface combines a variety of functions and options in a single system control panel and makes them as easy to use as possible – much like the house itself. Previous attempts to link electric vehicles and stationary energy systems together are characterized by their rather loose functional interconnection of different technical subsystems, each of which requires its own dedicated control system and operating devices. Generally speaking, building control systems are limited to operating a building and the immediate functions associated with it. The same applies to apps developed for electric vehicles (which indicate the state of charge, for example): as a rule, their functionality is confined to the vehicle itself. A dynamic, context-sensitive control system has been implemented to simplify interaction with the components. This interface orientates itself to the time of year and time of day as well as to the users’ routines, their location (at home or away) and their individual identities. The app is designed to simplify operation and increase comfort; it is thus able to suggest actions that assist the user. In addition, the interface offers the option of adding an “avatar”; this is designed to give the user positive motivation to lead a lifestyle that is as sustainable as possible. This gives the user positive emotional feedback and increases acceptance of the system.